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Extend handling for "long branch to RTS" to "long branch to jump leaving

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function".


git-svn-id: svn://svn.cc65.org/cc65/trunk@4368 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-10-15 11:11:20 +00:00
parent 635fae97fb
commit 1f489fd9e1
1 changed files with 53 additions and 26 deletions
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77
src/cc65/coptind.c
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@ -247,50 +247,77 @@ unsigned OptRTSJumps1 (CodeSeg* S)
unsigned OptRTSJumps2 (CodeSeg* S)
/* Replace long conditional jumps to RTS */
/* Replace long conditional jumps to RTS or to a final target */
{
unsigned Changes = 0;
/* Walk over all entries minus the last one */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
while (I < CS_GetEntryCount (S) - 1) {
/* Get the next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's an unconditional branch to a local target */
/* Check if it's an conditional branch to a local target */
if ((E->Info & OF_CBRA) != 0 && /* Conditional branch */
(E->Info & OF_LBRA) != 0 && /* Long branch */
E->JumpTo != 0 && /* Local label */
E->JumpTo->Owner->OPC == OP65_RTS && /* Target is an RTS */
(N = CS_GetNextEntry (S, I)) != 0) { /* There is a next entry */
E->JumpTo != 0) { /* Local label */
CodeEntry* X;
CodeLabel* LN;
opc_t NewBranch;
/* We will create a jump around an RTS instead of the long branch */
X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, E->JumpTo->Owner->LI);
CS_InsertEntry (S, X, I+1);
/* Get the jump target and the next entry. There's always a next
* entry, because we don't cover the last entry in the loop.
*/
CodeEntry* X = 0;
CodeEntry* T = E->JumpTo->Owner;
CodeEntry* N = CS_GetNextEntry (S, I);
/* Get the new branch opcode */
NewBranch = MakeShortBranch (GetInverseBranch (E->OPC));
/* Check if it's a jump to an RTS insn */
if (T->OPC == OP65_RTS) {
/* Get the label attached to N, create a new one if needed */
LN = CS_GenLabel (S, N);
/* It's a jump to RTS. Create a conditional branch around an
* RTS insn.
*/
X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, T->LI);
/* Generate the branch */
X = NewCodeEntry (NewBranch, AM65_BRA, LN->Name, LN, E->LI);
CS_InsertEntry (S, X, I+1);
} else if (T->OPC == OP65_JMP && T->JumpTo == 0) {
/* Delete the long branch */
CS_DelEntry (S, I);
/* It's a jump to a label outside the function. Create a
* conditional branch around a jump to the external label.
*/
X = NewCodeEntry (OP65_JMP, AM65_ABS, T->Arg, T->JumpTo, T->LI);
/* Remember, we had changes */
++Changes;
}
/* If we have a replacement insn, insert it */
if (X) {
CodeLabel* LN;
opc_t NewBranch;
/* Insert the new insn */
CS_InsertEntry (S, X, I+1);
/* Create a conditional branch with the inverse condition
* around the replacement insn
*/
/* Get the new branch opcode */
NewBranch = MakeShortBranch (GetInverseBranch (E->OPC));
/* Get the label attached to N, create a new one if needed */
LN = CS_GenLabel (S, N);
/* Generate the branch */
X = NewCodeEntry (NewBranch, AM65_BRA, LN->Name, LN, E->LI);
CS_InsertEntry (S, X, I+1);
/* Delete the long branch */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
}
/* Next entry */